Ariadne Oliver is accosted by the unpleasant Mrs Burton-Cox, whose son Desmond has hopes of marrying Ariadne’s beautiful goddaughter Celia Ravenscroft. But Mrs Burton-Cox will not give her blessings to the match until she learns the truth of the deaths of Celia’s parents, who were found shot to death on the grounds of their estate a decade before. Were they murdered, or was it a suicide pact? If they were murdered, who shot whom? Despite being insulted by the woman’s impertinence, Ariadne is nevertheless drawn to the cold case by curiosity, and resolves to find out the truth when she is persuaded by Celia herself. When she turns to Poirot for assistance, however, she finds him already preoccupied investigating the murder of an elderly psychiatrist who was the father of a personal friend. So Ariadne sets out to solve the Ravenscroft affair herself, with the mantra that ‘elephants can remember’ – no matter how much time has passed and how much people who were acquainted with the Ravenscrofts have aged, memories remain unchanged. However, the memories of the people Ariadne interviews are not as reliable as she has hoped, and soon the investigation takes a sinister turn when Desmond’s life is threatened by an unknown entity. When Poirot realizes that his investigation is inextricably linked with Mrs Oliver’s, the two join forces. With the help of a wigmaker, the evidence of a clever dog, and a French connection to the Ravenscroft case, Poirot is able to penetrate the fog of memory to uncover the truth of two long-ago deaths, and how that tragic story inspired the present-day killer whom he himself has been hunting.